Reduced Order Models Based On Pod Method For Wind Turbine Blade Design

In the aerodynamic design and analysis of modern wind turbine and blade, engineering method based on BEM is popular and dominating, because it's less time-consuming. As technology develops, the wind turbine and blade are becoming larger and larger, so the analysis and design require a higher accuracy. Taking into account the complex flow around the blade and geometry nonlinearity of deformation of flexible blades, we need a more precise model to obtain accurate simulation, in order to improve the design and optimization. Although the computational fluid dynamics can meet the need, it's severely limited by the high computational cost, and it is not widely used in engineering. This paper imports reduced-order models based on POD to the aerodynamic design and analysis of the wind turbine and blade. The model can maintain acceptable accuracy, and greatly reduce the computational cost. It's of great significance, for the blade design, the unsteady aerodynamic and aeroelastic analysis, turbine control, real-time simulation.Firstly, in the article, CFD method, as the full order model, is studied. Aerodynamic performance of NREL S809airfoil and NREL Phase VI10m wind rotor are simulated with CFD, considering different viscous models. The results are compared to wind tunnel test data to verify the reliability of the numerical simulation. Based on this, the basic theory of the reduced-order model is discussed. For Lid-driven cavity flow, the computational domain grid is simple, laminar flow state to the problem, direct application of reduced order model can be solved; for the flow around an airfoil of reduced-order model, with the2nd or3rd boundary conditions of the problems, resulting from the pressure inner product term, multiple linear regression modeling is developed; application of turbulent viscosity method of quasi-static POD with interpolation modeling, reduced order model is extended to the engineering application.Then the reduced-order models based on POD method applied in the most typical wind turbine static and dynamic stall problem, computational results show that the method can capture the flow of non-linear and unsteady effect, the lift coefficient, drag coefficient and pitching moment coefficients in the stall the process can be a good simulation of hysteresis.Finally, three-dimensional rotating coordinate system of reduced-order model is derived on the Coriolis force and centrifugal force generated by the source term, three-dimensional extension of the reduced order model is discussed.